Lateral Flow Device for Attachment to an Absorbent Article

ABSTRACT

A lateral flow device for testing a bodily fluid, such as urine, blood, mucous, saliva, etc., is provided. The lateral flow device is configured to be attached to an absorbent article via an attachment mechanism located on the lateral flow device or the absorbent article. The lateral flow device includes a chromatographic medium (e.g., porous membrane) that defines a detection zone that provides a signal indicative of the presence or absence of the analyte. The device may also include a control zone that provides a signal indicative of whether a sufficient amount of bodily fluid has been provided and tested. Regardless of its specific configuration, the lateral flow device is configured to be attached onto the absorbent article to provide a user or caregiver with rapid information about a health condition. For example, the device may be attached onto a diaper to provide information about the presence of enzymes or other compounds often encountered with a patient having a urinary tract infection. This information may provide an early warning system to allow the user or caregiver to seek additional testing and/or treatment. Alternatively, semi-quantitative or quantitative results may be derived from the test.

BACKGROUND OF THE INVENTION

Multiple tests have been developed for detecting components in urine.Such tests can provide information about overall health as well asprovide an indication of a health problem. When timely administered,such tests may also be able to provide an early indication of a healthproblem, which may be very advantageous for effective treatment. By wayof examples, urine testing can be used to detect urinary tractinfections, diabetes (including diabetic ketoacidosis), parasites,dehydration, dietary defects, cancer, high blood pressure, kidneydisease, asthma, severe emphysema, alcoholism, systemic lupuserythematosus (SLE), glomerulonephritis, and leukemia.

Such tests may be performed by having a patient voluntarily collect andprovide a sample. However, patient collected urine samples may not bereadily available with certain test subjects such as children, elderlyadults, and injured or non-ambulatory patients. Additionally, it may bepreferable to collect and test urine samples from these subjects atcertain times or conditions where the patient is not necessarily in thepresence of medical or otherwise specially trained personnel.Frequently, such subjects may be provided with a diaper or otherabsorbent article to collect urine. Then, the soiled article is providedto the medical or otherwise specially trained personnel for testing.

As such, a need exists for a device capable of testing bodily fluid thatcan be attached to an absorbent article such that the testing occurs atthe time of the insult of the absorbent article.

SUMMARY OF THE INVENTION

In general, an absorbent article for testing a bodily fluid suspected ofcontaining an analyte is disclosed. The absorbent article comprises anouter cover, a bodyside liner, and an absorbent core positioned betweenthe outer cover and the bodyside liner. A lateral flow device isattached to the bodyside liner of the absorbent article. The lateralflow device includes a chromatographic medium that defines a detectionzone. The detection zone is configured for exhibiting a signalindicative of the presence or absence of the analyte in the bodilyfluid.

In another embodiment, the present invention is generally directed to aninsert for testing a bodily fluid suspected of containing analyte. Theinsert includes a cover encasing a lateral flow device. Also, the insertincludes an attachment mechanism configured to attach the insert to abodyside liner of an absorbent article. In one embodiment, the insertcan also include an absorbent material encased within the cover.

In yet another embodiment, a method for detecting the presence orabsence of an analyte in urine is disclosed. The method includesattaching a lateral flow device to a bodyside liner of an absorbentarticle.

Other features and aspects of the present invention are described inmore detail below.

BRIEF DESCRIPTION OF THE DRAWINGS

A full and enabling disclosure of the present invention, including thebest mode thereof, directed to one of ordinary skill in the art, is setforth more particularly in the remainder of the specification, whichmakes reference to the appended figures in which:

FIG. 1 is a perspective view of an exemplary lateral flow device inaccordance with one embodiment of the present invention;

FIG. 2 is a perspective view of an exemplary attachment mechanism of thelateral flow device in accordance with one embodiment of the presentinvention;

FIG. 3 is a perspective view of another exemplary attachment mechanismof the lateral flow device in accordance with one embodiment of thepresent invention;

FIG. 4 is a perspective view of an exemplary use of the lateral flowdevice in conjunction with an absorbent article in accordance with oneembodiment of the present invention;

FIG. 5 is a perspective exploded view of an exemplary absorbent insertcontaining a lateral flow device for use with an absorbent article inaccordance with one embodiment of the present invention;

FIG. 6 is a perspective view of an absorbent insert containing a lateralflow device attached to an absorbent article in accordance with oneembodiment of the present invention; and

FIG. 7 is a perspective, exploded view of an absorbent article forattaching to a lateral flow device in accordance with one embodiment ofthe present invention.

Repeat use of reference characters in the present specification anddrawings is intended to represent same or analogous features or elementsof the invention.

Detailed Description of Representative Embodiments

Reference now will be made in detail to various embodiments of theinvention, one or more examples of which are set forth below. Eachexample is provided by way of explanation, not limitation of theinvention. In fact, it will be apparent to those skilled in the art thatvarious modifications and variations may be made in the presentinvention without departing from the scope or spirit of the invention.For instance, features illustrated or described as part of oneembodiment, may be used on another embodiment to yield a still furtherembodiment. Thus, it is intended that the present invention cover suchmodifications and variations.

Generally speaking, the present invention is directed to a lateral flowdevice for testing a bodily fluid (e.g., urine, blood, mucous, saliva,etc.) that can be attached to an absorbent article. Since lateral flowdevices are utilized to detect the presence or absence of compounds in abodily fluid, the manufacturing and packaging environment of the deviceis controlled to prevent contamination of the device prior to its use.Controlling the manufacturing environment adds costs to the manufactureof the device. If the device were to be integrated within theconstruction of the absorbent article (e.g., positioned within theabsorbent article's construction), then the manufacturing environment ofthe entire absorbent article would have to be controlled in order toprevent contamination of the device prior to its use, adding significantmanufacturing and packaging costs to the absorbent article. However,according to the present invention, the lateral flow device can beseparately manufactured under a controlled environment, and thenattached to an absorbent article by the user or caregiver. Thus, onlythe manufacturing environment of the lateral flow device is subject toregulation, saving the cost of regulating the manufacturing environmentof the absorbent article.

The lateral flow assay device generally includes a chromatographicmedium (e.g., porous membrane) that defines a detection zone forproviding a signal indicative of the presence or absence of an analyte.The device may also include a control zone that provides a signalindicative of whether a sufficient amount of bodily fluid has beenprovided and tested. Regardless of its specific configuration, thelateral flow assay device is configured to be attached to the absorbentarticle to provide a user or caregiver with rapid information about ahealth condition. For example, the device may be attached to a diaper toprovide information about the presence of enzymes or other compoundsoften encountered with a patient having a urinary tract infection. Thisinformation may provide an early warning system to allow the user orcaregiver to seek additional testing and/or treatment. Alternatively,semi-quantitative or quantitative results may be derived from the test.

I. Lateral Flow Assay Device

Generally speaking, a lateral flow assay device is employed in thepresent invention to perform a heterogeneous assay. A heterogeneousassay is one in which a species is separated from another species priorto detection. Separation may be carried out by physical separation,e.g., by transferring one of the species to another reaction vessel,filtration, centrifugation, chromatography, solid phase capture,magnetic separation, and so forth. The separation may also benonphysical in that no transfer of one or both of the species isconducted, but the species are separated from one another in situ. Insome embodiments, for example, a heterogeneous immunoassay is performedthat utilizes mechanisms of the immune systems, wherein antibodies areproduced in response to the presence of antigens that are pathogenic orforeign to the organisms. These antibodies and antigens, i.e.,immunoreactants, are capable of binding with one another, therebycausing a highly specific reaction mechanism that may be used todetermine the presence or concentration of that particular antigen in afluid test sample. In other embodiments, however, the heterogeneousassay may employ non-specific chemical reactions to achieve the desiredseparation.

In any event, the use of a lateral flow assay device provides a varietyof benefits, including a more uniform flow of the bodily fluid andreagents during testing. This may enhance the accuracy of the test andminimize the need for external control mechanisms. Referring to FIG. 1,for example, one embodiment of a lateral flow assay device 10 will nowbe described in more detail. As shown, the device 10 contains achromatographic medium 14 optionally supported by a rigid support 12.The chromatographic medium 14 may be made from any of a variety ofmaterials through which the test sample is capable of passing. Forexample, the chromatographic medium 14 may be a porous membrane formedfrom synthetic or naturally occurring materials, such as polysaccharides(e.g., cellulose materials such as paper and cellulose derivatives, suchas cellulose acetate and nitrocellulose); polyether sulfone;polyethylene; nylon; polyvinylidene fluoride (PVDF); polyester;polypropylene; silica; inorganic materials, such as deactivated alumina,diatomaceous earth, MgSO₄, or other inorganic finely divided materialuniformly dispersed in a porous polymer matrix, with polymers such asvinyl chloride, vinyl chloride-propylene copolymer, and vinylchloride-vinyl acetate copolymer; cloth, both naturally occurring (e.g.,cotton) and synthetic (e.g., nylon or rayon); porous gels, such assilica gel, agarose, dextran, and gelatin; polymeric films, such aspolyacrylamide; and so forth. In one particular embodiment, thechromatographic medium 14 is formed from nitrocellulose and/or polyethersulfone materials. It should be understood that the term“nitrocellulose” refers to nitric acid esters of cellulose, which may benitrocellulose alone, or a mixed ester of nitric acid and other acids,such as aliphatic carboxylic acids having from 1 to 7 carbon atoms.

The size and shape of the chromatographic medium 14 may generally varyas is readily recognized by those skilled in the art. For instance, aporous membrane strip may have a length of from about 10 to about 100millimeters, in some embodiments from about 20 to about 80 millimeters,and in some embodiments, from about 40 to about 60 millimeters. Thewidth of the membrane strip may also range from about 0.5 to about 20millimeters, in some embodiments from about 1 to about 15 millimeters,and in some embodiments, from about 2 to about 10 millimeters. Likewise,the thickness of the membrane strip is generally small enough to allowtransmission-based detection. For example, the membrane strip may have athickness less than about 500 micrometers, in some embodiments less thanabout 250 micrometers, and in some embodiments, less than about 150micrometers.

As stated above, the support 12 carries the chromatographic medium 14.For example, the support 12 may be positioned directly adjacent to thechromatographic medium 14 as shown in FIG. 1, or one or more interveninglayers may be positioned between the chromatographic medium 14 and thesupport 12. Regardless, the support 12 may generally be formed from anymaterial able to carry the chromatographic medium 14. The support 12 maybe formed from a material that is transmissive to light, such astransparent or optically diffuse (e.g., transluscent) materials. Also,it is generally desired that the support 12 is liquid-impermeable sothat fluid flowing through the medium 14 does not leak through thesupport 12. Examples of suitable materials for the support include, butare not limited to, glass; polymeric materials, such as polystyrene,polypropylene, polyester (e.g., Mylar® film), polybutadiene,polyvinylchloride, polyamide, polycarbonate, epoxides, methacrylates,and polymelamine; and so forth. To provide a sufficient structuralbacking for the chromatographic medium 14, the support 12 is generallyselected to have a certain minimum thickness. Likewise, the thickness ofthe support 12 is typically not so large as to adversely affect itsoptical properties. Thus, for example, the support 12 may have athickness that ranges from about 100 to about 5,000 micrometers, in someembodiments from about 150 to about 2,000 micrometers, and in someembodiments, from about 250 to about 1,000 micrometers. For instance,one suitable membrane strip having a thickness of about 125 micrometersmay be obtained from Millipore Corp. of Bedford, Mass. under the name“SHF180UB25.”

The chromatographic medium 14 may be cast onto the support 12, whereinthe resulting laminate may be die-cut to the desired size and shape.Alternatively, the chromatographic medium 14 may simply be laminated tothe support 12 with, for example, an adhesive. In some embodiments, anitrocellulose or nylon porous membrane is adhered to a Mylar® film. Anadhesive is used to bind the porous membrane to the Mylar® film, such asa pressure-sensitive adhesive. Laminate structures of this type arebelieved to be commercially available from Millipore Corp. of Bedford,Mass. Still other examples of suitable laminate device structures aredescribed in U.S. Pat. No. 5,075,077 to Durley, III, et al., which isincorporated herein in its entirety by reference thereto for allpurposes.

The device 10 may also contain an absorbent material 18 that ispositioned adjacent to the medium 14. The absorbent material 18 can helppromote capillary action and fluid flow through the medium 14. Inaddition, the absorbent material 18 receives fluid that has migratedthrough the entire chromatographic medium 14 and thus draws anyunreacted components away from the detection region to help reduce thelikelihood of “false positives.” Some suitable absorbent materials thatmay be used in the present invention include, but are not limited to,nitrocellulose, cellulosic materials, porous polyethylene pads, glassfiber filter paper, and so forth. The absorbent material may be wet ordry prior to being incorporated into the device. Pre-wetting mayfacilitate capillary flow for some fluids, but is not typicallyrequired. Also, as is well known in the art, the absorbent material maybe treated with a surfactant to assist the wicking process.

To initiate the detection of an analyte, the bodily fluid (e.g., urine)may be applied to a portion of the chromatographic medium 14 throughwhich it may then travel in the direction illustrated by arrow “L” inFIG. 1. Alternatively, the fluid may first contact a sample applicationzone 16 that is in fluid communication with the chromatographic medium14. The sample application zone 16 may be defined by a separate pad ormaterial as shown in FIG. 1, or simply defined by the chromatographicmedium 14. In the illustrated embodiment, the fluid may travel from thesample application zone 16 to a conjugate pad (not shown) that is placedin communication with one end of the sample pad. The conjugate pad maycontain one or more diffusively immobilized reagents, and be formed froma material through which a fluid is capable of passing (e.g., glassfibers). Some suitable materials that may be used to form the absorbentmaterial 18 and/or sample pad include, but are not limited to,nitrocellulose, cellulose, porous polyethylene pads, and glass fiberfilter paper. If desired, the sample pad may also contain one or moreassay pretreatment reagents, either diffusively or non-diffusivelyattached thereto.

Regardless of the particular manner in which it is formed, the lateralflow assay device of the present invention employs one or more zones forproviding an indicator of the presence of an analyte. More specifically,such zone(s) typically contain a chemical or biological reagent thatinteracts with the analyte and/or other reagents to generate a signal(e.g., visual signal). Referring again to FIG. 1, for example, thelateral flow assay device 10 includes a detection zone 20 within which acapture reagent is disposed. Typically, the capture reagent is appliedin a manner so that it does not substantially diffuse through the matrixof the chromatographic medium 14 (i.e., non-diffusively immobilized).This enables a user to readily detect the change in color that occursupon reaction of the capture reagent with other compounds. The capturereagent may, for example, form an ionic and/or covalent bond withfunctional groups present on the surface of the chromatographic medium14 so that it remains immobilized thereon. For instance, particles, suchas described below, may facilitate the immobilization of the reagent atthe detection zone 20. Namely, the reagent may be coated onto particles,which are then immobilized on the chromatographic medium 14 of thedevice 10. In this manner, the reagent is able to readily contactcompounds flowing through the medium 14.

Another zone that may be employed in the lateral flow assay device 10for improving detection accuracy is a control zone 22. The control zone22 gives a signal to the user that the test is performing properly. Morespecifically, reagents may be employed that flow through thechromatographic medium 14 upon contact with a sufficient volume of thebodily fluid being tested. These reagents may then be observed, eithervisually or with an instrument, within the control zone 22. The controlreagents generally contain a detectable substance, such as luminescentcompounds (e.g., fluorescent, phosphorescent, etc.); radioactivecompounds; visual compounds (e.g., colored dye or metallic substance,such as gold); liposomes or other vesicles containing signal-producingsubstances; enzymes and/or substrates, and so forth. Other suitabledetectable substances may be described in U.S. Pat. Nos. 5,670,381 toJou, et al. and 5,252,459 to Tarcha et al., which are incorporatedherein in their entirety by reference thereto for all purposes.

If desired, one or more of the reagents employed in the assay device maybe disposed on particles (sometimes referred to as “beads” or“microbeads”). Among other things, the particles enhance the ability ofthe reagent to travel through a chromatographic medium. For instance,naturally occurring particles, such as nuclei, mycoplasma, plasmids,plastids, mammalian cells (e.g., erythrocyte ghosts), unicellularmicroorganisms (e.g., bacteria), polysaccharides (e.g., agarose), etc.,may be used. Further, synthetic particles may also be utilized. Forexample, in one embodiment, latex microparticles that are labeled with afluorescent or colored dye are utilized. Although any synthetic particlemay be used in the present invention, the particles are typically formedfrom polystyrene, butadiene styrenes, styreneacrylic-vinyl terpolymer,polymethylmethacrylate, polyethylmethacrylate, styrene-maleic anhydridecopolymer, polyvinyl acetate, polyvinylpyridine, polydivinylbenzene,polybutyleneterephthalate, acrylonitrile, vinylchloride-acrylates, andso forth, or an aldehyde, carboxyl, amino, hydroxyl, or hydrazidederivative thereof. When utilized, the shape of the particles maygenerally vary. In one particular embodiment, for instance, theparticles are spherical in shape. However, it should be understood thatother shapes are also contemplated by the present invention, such asplates, rods, discs, bars, tubes, irregular shapes, etc. In addition,the size of the particles may also vary. For instance, the average size(e.g., diameter) of the particles may range from about 0.1 nanometers toabout 1,000 microns, in some embodiments, from about 0.1 nanometers toabout 100 microns, and in some embodiments, from about 1 nanometer toabout 10 microns. Commercially available examples of suitable particlesinclude fluorescent carboxylated microspheres sold by Molecular Probes,Inc. under the trade names “FluoSphere” (Red 580/605) and“TransfluoSphere” (543/620), as well as “Texas Red” and 5- and6-carboxytetramethylrhodamine, which are also sold by Molecular Probes,Inc. In addition, commercially available examples of suitable colored,latex microparticles include carboxylated latex beads sold by Bang'sLaboratory, Inc.

The location of the detection zone 20 and control zone 22 may vary basedon the nature of the test being performed. In the illustratedembodiment, for example, the control zone 22 is defined by thechromatographic medium 14 and positioned downstream from the detectionzone 20. In such embodiments, the control zone 22 may contain a materialthat is non-diffusively immobilized in the manner described above andforms a chemical and/or physical bond with the control reagents. Whenthe control reagents contain latex particles, for instance, the controlzone 22 may include a polyelectrolyte that binds to the particles.Various polyelectrolytic binding systems are described, for instance, inU.S. Patent App. Publication No. 2003/0124739 to Song, et al., which isincorporated herein in it entirety by reference thereto for allpurposes. In alternative embodiments, however, the control zone 22 maysimply be defined by a region of the absorbent material 18 to which thecontrol reagents flow after traversing through the chromatographicmedium 14.

Regardless of the particular control technique selected, the applicationof a sufficient volume of the test sample to the device 10 will cause asignal to form within the control zone 22, whether or not the enzyme orother analyte of interest is present. Among the benefits provided bysuch a control zone is that the user or other personnel are informedthat a sufficient volume of test sample has been added without requiringcareful measurement or calculation. This provides the ability to use thelateral flow assay device 10 without the need for externally controllingthe reaction time, test sample volume, etc. In the case of the elderly,children, or patients unable to communicate clearly, control zone 22provides an indication that a sample was discharged, collected, andsuccessfully tested.

The detection zone 20, control zone 22, or any other zone employed inthe lateral flow assay device 10 may generally provide any number ofdistinct detection regions so that a user may better determine theconcentration of the enzyme or other analyte within the test sample.Each region may contain the same or different materials. For example,the zones may include two or more distinct regions (e.g., lines, dots,etc.). The regions may be disposed in the form of lines in a directionthat is substantially perpendicular to the flow of the test samplethrough the device 10. Likewise, in some embodiments, the regions may bedisposed in the form of lines in a direction that is substantiallyparallel to the flow of the test sample through the device 10.

The specific reagents employed in the lateral flow assay device dependon the analyte of interest and the assay technique employed. In oneparticular embodiment, for example, it may be desirable to detect thepresence of leukocytes in urine as an early diagnosis of urinary tractinfection (“UTI”). Although leukocytes are normally present in theurine, it has been determined that the threshold limit for pathologicallevels is about 1×10⁴ leukocytes per milliliter of uncentrifuged urine.When leukocytes are present in urine, leukocyte esterase is produced andmay be used as a biomarker for the presence of leukocytes.

A variety of reagents may be used for detecting the presence of theleukocyte esterase enzyme. One such reagent is a substrate that ischemically acted upon or “cleaved” by the enzyme of interest to releasea product. For example, the substrate may be an ester that iscatalytically hydrolyzed in the presence of leukocyte esterase to yieldan aromatic compound. The aromatic esters may include, for instance,indoxyl esters having the following general formula:

wherein, R may be substituted or unsubstituted, and may be an alkylgroup, an alkyoxy group, a hydroxyalkyl group, an alkylene group, afatty acid group, and so forth. In addition, the aromatic rings may alsobe substituted or unsubstituted. Specific examples include, forinstance, indoxyl acetate, indoxyl butyrate, indoxyl laureate, indoxylstearate, indoxyl ester of a N-blocked amino acid or peptide andthioindoxyl analogs thereof, and N-Tosyl-L-alanine 3-indoxyl ester. Suchindoxyl esters are hydrolyzed by the leukocyte esterase to form abenzopyrrole, such as indoxyl, which has the following structure:

Lactate esters may also be used, such as described in U.S. Pat. Nos.5,464,739 to Johnson, et al. and 5,663,044 to Noffsinger, et al., whichare incorporated herein in their entirety by reference thereto for allpurposes. Lactate esters are generally hydrolyzed by the leukocyteesterase to provide a hydroxy-pyrrole compound. Other suitable estersubstrates include thiazole esters, pyrrole esters, thiophene esters,naphthyl esters, phenoxyl esters, quinolinyl esters, such as describedin U.S. Pat. Nos. 5,750,359 to Huh et al.; 4,657,855 to Corey, et al.;and Japanese Publication No. 03210193 to Kawanishi, et al., which areincorporated herein in their entirety by reference thereto for allpurposes.

Typically, the substrate is diffusively immobilized on the lateral flowassay device 10 prior to application of the urine or other bodily fluid.The substrate is preferably disposed downstream from the sampleapplication zone 16. In this manner, the test sample is capable ofmixing with the enzyme upon application. If desired, the pH may bemaintained at a relatively neutral level to facilitate the desiredenzyme-catalyzed reaction, such as described above. To accomplish thedesired pH level, a buffer may be mixed with the substrate prior toapplication to the device 10. Alternatively, the buffer may beseparately applied to the lateral flow assay device 10 so that it iscapable of mixing with the reagents upon exposure the bodily fluid beingtested.

Regardless, an aromatic compound is released through cleavage of thesubstrate that is capable of inducing a color change in the presence ofcertain reagents. The released aromatic compound is a nucleophile inthat it contains a group that is electron rich (e.g., amine) and thatmay form bonds with electron deficient groups. For example, indoxylesters are hydrolyzed by the leukocyte esterase to form indoxyl. Indoxylcontains an electron-rich, aromatic ring system that is capable ofundergoing electrophilic attack by a diazonium ion having the genericformula:

The diazonium ion may be zwitterionic in that the counterion of thediazonium moiety is covalently bound to the ring system. The ring systemof the diazonium ion may be substituted or unsubstituted. The ion may beprovided by a variety of suitable diazonium salts, such as diazoniumchlorides, diazonium acid sulphates, diazonium alkyl sulphates,diazonium fluoborates, diazonium benzenesulphonates, diazonium acid1,5-naphthalenedisulphonates, and so forth. Specific examples ofdiazonium salts are 1-diazo-2-naphthol-4-sulfonate;1-diazophenyl-3-carbonate; 4-diazo-3-hydroxy-1-naphthylsulfonate (DNSA);4-diazo-3-hydroxy-7-nitro-1-naphthylsulfonate (NDNSA);4-diazo-3-hydroxy-1,7-naphthyldisulfonate; 2-methoxy-4-(N-morpholinyl)benzene diazonium chloride;4-diazo-3-hydroxy-7-bromo-1-naphthylsulfonate; and4-diazo-3-hydroxy-7-[1, oxopropyl]-1-naphthylsulfonate. One particularlydesired diazonium salt is 5-chloro-2-methoxybenzenediazonium chloride,which has a yellow color and is classified under the name “Diazo Red RC”or “Fast Red RC.” More specifically, “Fast Red RC” has the followingstructure:

Other suitable diazonium salts are classified by the common names “FastRed B” and “Fast Blue B.” Still other suitable diazonium salts may bedescribed in U.S. Pat. Nos. 4,637,979 to Skjold, et al.; 4,806,423 toHugh, et al.; and 4,814,271 to Hugl, et al., which are incorporatedherein in their entirety by reference thereto for all purposes.

As indicated above, the nucleophilic aromatic compounds released by thehydrolysis of the substrate are capable of undergoing electrophilicattack by a reagent (e.g., diazonium ion). This reaction is oftenreferred to as “coupling” and results in the formation of anotherreagent having a different color. For example, diazonium ions may reactwith aromatic compounds to form an aromatic azo compound having thegeneric formula, R—N═N—R′, wherein “R” and “R′” are aryl groups. Withoutintending to be limited by theory, it is believed that this reactioninduces either a shift of the absorption maxima towards the red end ofthe spectrum (“bathochromic shift”) or towards the blue end of thespectrum (“hypsochromic shift”). The type of absorption shift depends onthe nature of the resulting azo molecule and whether it functions as anelectron acceptor (oxidizing agent), in which a hypsochromic shiftresults, or whether it functions as an electron donor (reducing agent),in which a bathochromic shift results. The absorption shift provides acolor difference that is detectable, either visually or throughinstrumentation, to indicate the presence of leukocyte esterase or otherenzymes within the test sample. For example, prior to contact with aninfected test sample, the diazonium ion may be colorless or it maypossess a certain color. However, after contacting the test sample andreacting with an aromatic compound released by hydrolysis of thesubstrate, an aromatic azo compound will form that exhibits a color thatis different than the initial color of the diazonium ion. Exemplaryaromatic azo compounds that may be formed include dimethyldiazene,diphenydiazene, 1-naphthyl-2-naphthyl diazene,3-chlorophenyl-4-chlorophenyl diazene, methylvinyl diazene, and2-naphthylphenyl diazene. In one particular embodiment, for instance,“Fast Red RC” (yellow), a diazonium ion, may react with indoxyl to forman aromatic azo compound that is red and has the following generalstructure (may be substituted or unsubstituted):

Normally, the above-described diazonium ion is immobilized within thedetection zone 20 of the lateral flow assay device 10. The diazonium ionmay be applied directly to the medium 14 or first formed into a solutionprior to application. Various solvents may be utilized to form thesolution, such as, but not limited to, acetonitrile, dimethylsulfoxide(DMSO), ethyl alcohol, dimethylformamide (DMF), and other polar organicsolvents. For instance, the amount of a diazonium salt in the solutionmay range from about 0.001 to about 100 milligrams per milliliter ofsolvent, and in some embodiments, from about 0.1 to about 10 milligramsper milliliter of solvent. In one particular embodiment, the detectionzone 20 is defined by the chromatographic medium 14 and formed bycoating a solution thereon using well-known techniques and then dried.The diazonium ion concentration may be selectively controlled to providethe desired level of detection sensitivity.

Typically, the diazonium ion is applied in a manner so that it does notsubstantially diffuse through the matrix of the chromatographic medium14 (i.e., non-diffusively immobilized), which enables a user to readilydetect the change in color that occurs upon reaction of the diazoniumion with a nucleophilic aromatic compound. The diazonium ion may form anionic and/or covalent bond with functional groups present on the surfaceof the chromatographic medium 14 so that it remains immobilized thereon.For instance, particles, such as described below, may facilitate theimmobilization of the diazonium ion at the detection zone 20. Namely,the diazonium ion may be coated onto particles, which are thenimmobilized on the chromatographic medium 14 of the device 10. In thismanner, the diazonium ion is able to readily contact nucleophilicaromatic compounds flowing through the medium 14.

One benefit of the lateral flow assay device is its ability to readilyincorporate one or more additional reagent zones to facilitate thedesired reactions. By way of example, a reagent zone (not shown) may beutilized. In the illustrated embodiment, the reagent zone may be locatedsuch that test sample travels from the sample application zone 16 to areagent zone that is in fluid communication with the sample applicationzone 16. The reagent zone may be formed on the medium 14. Alternatively,the reagent zone may be formed from a separate material or pad. Such areagent pad may be formed from any material through which the testsample is capable of passing, such as glass fibers.

In addition to the zones specified above, the lateral flow assay device10 may also include other optional zones. For example, the lateral flowassay device 10 may include an accelerator zone (not shown) in which iscontained an accelerator for the enzyme-catalyzed substrate reaction.Typically, the accelerator is diffusively immobilized within theaccelerator zone in the manner described above so that it may flowthrough the medium 14 upon contact with the test sample. The location ofthe accelerator zone may generally vary, so long as it positionedupstream from the detection zone 20. For example, in some embodiments,the accelerator zone may be positioned at a location (e.g., sampleapplication zone 16) that is upstream from the application of thesubstrate (e.g., reagent zone). Due to the separation provided betweenthe substrate and accelerator, the likelihood of any premature reactiontherebetween is thus reduced. It should be understood, however, that theaccelerator may nevertheless be combined with the substrate in someapplications.

Another zone that may be employed is a quenching zone (not shown). Thequenching zone is configured to remove compounds from the test samplethat would otherwise interfere with the accuracy of the detectionsystem. For example, contaminants within the test sample (e.g.,phenolics, bilirubin, urobilinogen, etc.) may react with the diazoniumion within the detection zone 20 and form an aromatic azo compound,thereby producing a “false negative” result. Thus, the quenching zonemay contain a quenching agent, such as a diazonium ion, that is capableof reacting with the reaction contaminants. The quenching agent may bethe same or different than the detection agent used within the detectionzone 20. Typically, the quenching agent is non-diffusively immobilizedwithin the quenching zone in the manner described above so that it doesnot flow through the medium 14 and interfere with testing. The locationof the quenching zone may vary, but is typically positioned upstreamfrom the detection zone 20 and the location at which the substrate isapplied to avoid interference with enzyme detection. For example, in theillustrated embodiment, the quenching zone may be positioned immediatelydownstream of the sample application zone 16 and over medium 14.Alternatively, the quenching zone may be positioned upstream from thesample application zone 16.

An exemplary method for detecting the presence of leukocyte esterasewithin a test sample using the device 10 of FIG. 1 will now be describedin more detail. Initially, urine containing leukocyte esterase isdischarged to the sample application zone 16 and travels in thedirection “L” to a reagent zone. At the reagent zone, the esterase isable to mix with and begin to initiate the catalytic reaction. Whileflowing through the medium, the enzyme and substrate react to release anaromatic product that subsequently couples with a diazonium ion to forma colored aromatic azo compound in the detection zone 20. After thereaction, the detection zone 20 changes color, which may be indicativeof urinary tract infection. Due to the nature of the controlled fluidflow, any unreacted substrate travels to the end of the reaction mediumso that it is unable to adversely interfere with observance of thearomatic azo compound in the detection region.

Of course, the present invention is by no means limited to the diagnosisof urinary tract infection. Numerous health conditions may be diagnosedthrough testing of bodily fluids such as urine. Testing for even asingle condition may require that multiple different analytes betargeted. By way of example, the assay device may employ specificbinding pairs to test for the presence of certain biological analytes(e.g., antibodies, antigens, etc.). Specific binding members generallyrefer to a member of a specific binding pair, i.e., two differentmolecules where one of the molecules chemically and/or physically bindsto the second molecule. For instance, immunoreactive specific bindingmembers may include antigens, haptens, aptamers, antibodies (primary orsecondary), and complexes thereof, including those formed by recombinantDNA methods or peptide synthesis. An antibody may be a monoclonal orpolyclonal antibody, a recombinant protein or a mixture(s) orfragment(s) thereof, as well as a mixture of an antibody and otherspecific binding members. The details of the preparation of suchantibodies and their suitability for use as specific binding members arewell known to those skilled in the art. Other common specific bindingpairs include but are not limited to, biotin and avidin (or derivativesthereof), biotin and streptavidin, carbohydrates and lectins,complementary nucleotide sequences (including probe and capture nucleicacid sequences used in DNA hybridization assays to detect a targetnucleic acid sequence), complementary peptide sequences including thoseformed by recombinant methods, effector and receptor molecules, hormoneand hormone binding protein, enzyme cofactors and enzymes, enzymeinhibitors and enzymes, and so forth. Furthermore, specific bindingpairs may include members that are analogs of the original specificbinding member. For example, a derivative or fragment of the analyte,i.e., an analyte-analog, may be used so long as it has at least oneepitope in common with the analyte.

Still other analytes of interest may include proteins, enzymes,nitrites, ketones, various bacteria, red or white blood cells, glucose,bilirubin, urobilinogen, and so forth. By way of example, the presenceof nitrites in urine may indicate a urinary tract infection or evenother bacterial infections in the body. To test for the presence ofnitrites, the assay device may, for example, employ a substratediffusively immobilized on the chromatographic medium that includes bothan aromatic amine and another aromatic compound. The amine is selectedso that it will react with the nitrite to form a diazonium salt. Thesalt, in turn, may react with the aromatic compound to generate an azodye that provides a visual indication, by a color change, that nitritehas been detected.

II. Absorbent Article

In accordance with the present invention, one or more lateral flow assaydevices can be attached to an absorbent article. An “absorbent article”generally refers to any article capable of absorbing water or otherfluids. Examples of some absorbent articles include, but are not limitedto, personal care absorbent articles, such as diapers, training pants,absorbent underpants, incontinence articles, feminine hygiene products(e.g., sanitary napkins), swim wear, baby wipes, and so forth; medicalabsorbent articles, such as garments, fenestration materials, underpads,bedpads, bandages, absorbent drapes, and medical wipes; food servicewipers; clothing articles; and so forth. Materials and processessuitable for forming such absorbent articles are well known to thoseskilled in the art. Typically, absorbent articles include asubstantially liquid-impermeable layer (e.g., outer cover), aliquid-permeable layer (e.g., bodyside liner, surge layer, etc.), and anabsorbent core.

In some embodiments, such as those where the lateral flow device has itsown attachment mechanism, the absorbent article does not need anyspecial features or configuration. Thus, the absorbent article can haveany configuration desired. Alternatively, the absorbent article can beconfigured for attaching to a lateral flow device, as explained ingreater detail below.

Various embodiments of an absorbent article that may be formed accordingto the present invention will now be described in more detail. Forpurposes of illustration only, an absorbent article is shown in FIG. 4as a diaper 100. In the illustrated embodiment, the diaper 100 is shownas having an hourglass shape in an unfastened configuration. However,other shapes may of course be utilized, such as a generally rectangularshape, T-shape, or I-shape. The diaper 100 includes a chassis formed byvarious components, generally including an absorbent core positionedbetween an outer cover 104 and a bodyside liner 102. It should beunderstood, however, that other layers may also be used in exemplaryembodiments of the present invention. For example, a surge layer may bepresent in the construction of the absorbent article, such as thosesurge layers described in U.S. Pat. No. 5,486,166 to Ellis et al. andU.S. Pat. No. 5,490,846 to Ellis et al., which are incorporated hereinin their entirety by reference thereto for all purposes. Likewise, oneor more of the layers referred to in FIG. 4 may also be eliminated incertain exemplary embodiments of the present invention.

The bodyside liner 102 is generally employed to help isolate thewearer's skin from liquids held in the absorbent core. For example, theliner 102 presents a bodyfacing surface that is typically compliant,soft feeling, and non-irritating to the wearer's skin. Typically, theliner 102 is also less hydrophilic than the absorbent core so that itssurface remains relatively dry to the wearer. As indicated above, theliner 102 may be liquid-permeable to permit liquid to readily penetratethrough its thickness. Exemplary liner constructions that contain anonwoven web are described in U.S. Pat. Nos. 5,192,606 to Proxmire, etal.; 5,702,377 to Collier, IV, et al.; 5,931,823 to Stokes, et al.;6,060,638 to Paul, et al.; and 6,150,002 to Varona, as well as U.S.Patent Application Publication Nos. 2004/0102750 to Jameson;2005/0054255 to Morman, et al.; and 2005/0059941 to Baldwin, et al., allof which are incorporated herein in their entirety by reference theretofor all purposes.

The outer cover 104 is typically formed from a material that issubstantially impermeable to liquids. For example, the outer cover 104may be formed from a thin plastic film or other flexibleliquid-impermeable material. In one embodiment, the outer cover 104 isformed from a polyethylene film having a thickness of from about 0.01millimeter to about 0.05 millimeter. The film may be impermeable toliquids, but permeable to gases and water vapor (i.e., “breathable”).This permits vapors to escape from the absorbent core 103, but stillprevents liquid exudates from passing through the outer cover 104. If amore cloth-like feeling is desired, the outer cover 104 may be formedfrom a polyolefin film laminated to a nonwoven web. For example, astretch-thinned polypropylene film may be thermally laminated to aspunbond web of polypropylene fibers.

Besides the above-mentioned components, the diaper 100 may also containvarious other components as is known in the art. For example, the diaper100 may also contain a substantially hydrophilic tissue wrapsheet (notillustrated) that helps maintain the integrity of the fibrous structureof the absorbent core. The tissue wrapsheet is typically placed aboutthe absorbent core 103 over at least the two major facing surfacesthereof, and composed of an absorbent cellulosic material, such ascreped wadding or a high wet-strength tissue. The tissue wrapsheet maybe configured to provide a wicking layer that helps to rapidlydistribute liquid over the mass of absorbent fibers of the absorbentcore. The wrapsheet material on one side of the absorbent fibrous massmay be bonded to the wrapsheet located on the opposite side of thefibrous mass to effectively entrap the absorbent core. Furthermore, thediaper may also include a ventilation layer (not shown) that ispositioned between the absorbent core and the outer cover 104. Whenutilized, the ventilation layer may help insulate the outer cover 104from the absorbent core, thereby reducing dampness in the outer cover104. Examples of such ventilation layers may include a nonwoven weblaminated to a breathable film, such as described in U.S. Pat. No.6,663,611 to Blaney, et al., which is incorporated herein in itsentirety by reference thereto for all purposes.

In some embodiments, the diaper 100 may also include a pair of sidepanels (or ears) (not shown) that extend from the side edges of thediaper 100 into one of the waist regions. The side panels may beintegrally formed with a selected diaper component. For example, theside panels may be integrally formed with the outer cover 104 or fromthe material employed to provide the top surface. In alternativeconfigurations, the side panels may be provided by members connected andassembled to the outer cover 104, the top surface, between the outercover 104 and top surface, or in various other configurations. Ifdesired, the side panels may be elasticized or otherwise renderedelastomeric by use of the elastic nonwoven composite of the presentinvention. Examples of absorbent articles that include elasticized sidepanels and selectively configured fastener tabs are described in PCTPatent Application WO 95/16425 to Roessler; U.S. Pat. No. 5,399,219 toRoessler et al.; U.S. Pat. No. 5,540,796 to Fries; and U.S. Pat. No.5,595,618 to Fries, each of which is incorporated herein in its entiretyby reference thereto for all purposes.

The diaper 100 may also include a pair of containment flaps that areconfigured to provide a barrier and to contain the lateral flow of bodyexudates. The containment flaps may be located along the laterallyopposed side edges of the bodyside liner 102 adjacent the side edges ofthe absorbent core. The containment flaps may extend longitudinallyalong the entire length of the absorbent core, or may only extendpartially along the length of the absorbent core. When the containmentflaps are shorter in length than the absorbent core, they may beselectively positioned anywhere along the side edges of diaper 100 in acrotch region 109. In one embodiment, the containment flaps extend alongthe entire length of the absorbent core to better contain the bodyexudates. Such containment flaps are generally well known to thoseskilled in the art. For example, suitable constructions and arrangementsfor the containment flaps are described in U.S. Pat. No. 4,704,116 toEnloe, which is incorporated herein in its entirety by reference theretofor all purposes.

To provide improved fit and to help reduce leakage of body exudates, thediaper 100 may be elasticized with suitable elastic members, as furtherexplained below. For example, as representatively illustrated in FIG. 4,the diaper 100 may include leg elastics 106 constructed to operablytension the side margins of the diaper 100 to provide elasticized legbands which can closely fit around the legs of the wearer to reduceleakage and provide improved comfort and appearance. Waist elastics 108may also be employed to elasticize the end margins of the diaper 100 toprovide elasticized waistbands. The waist elastics 108 are configured toprovide a resilient, comfortably close fit around the waist of thewearer.

The diaper 100 may also include one or more fasteners. For example, twoflexible fasteners can be on opposite side edges of waist regions tocreate a waist opening and a pair of leg openings about the wearer. Theshape of the fasteners may generally vary, but may include, forinstance, generally rectangular shapes, square shapes, circular shapes,triangular shapes, oval shapes, linear shapes, and so forth. Thefasteners may include, for instance, a hook-and-loop material, buttons,pins, snaps, adhesive tape fasteners, cohesives, fabric-and-loopfasteners, etc. In one particular embodiment, each fastener includes aseparate piece of hook material affixed to the inside surface of aflexible backing.

The various regions and/or components of the diaper 100 may be assembledtogether using any known attachment mechanism, such as adhesive,ultrasonic, thermal bonds, etc. Suitable adhesives may include, forinstance, hot melt adhesives, pressure-sensitive adhesives, and soforth. When utilized, the adhesive may be applied as a uniform layer, apatterned layer, a sprayed pattern, or any of separate lines, swirls ordots. In the illustrated embodiment, for example, the outer cover 104and bodyside liner 102 are assembled to each other and to the absorbentcore using an adhesive. Alternatively, the absorbent core may beconnected to the outer cover 104 using conventional fasteners, such asbuttons, hook and loop type fasteners, adhesive tape fasteners, and soforth. Similarly, other diaper components, such as the leg elasticmembers 106, waist elastic members 108 and fasteners, may also beassembled into the diaper 100 using any attachment mechanism.

III. Attachment Mechanisms

Generally speaking, the lateral flow assay device may be attached ontothe absorbent article in a variety of different orientations andconfigurations, so long as the device is capable of receiving the bodilyfluid and providing a signal to a user or caregiver of the presence orabsence of the analyte. In one embodiment, the detection zone and/orcontrol zone can be visible to the user or caregiver so that a simple,accurate, and rapid indication of the presence of the analyte may beprovided even when the absorbent article is being worn. The visibilityof such zone(s) may be accomplished in a variety of ways. For example,in some embodiments, the absorbent article may include a transparent ortransluscent portion (e.g., window, film, etc.) that allows thedetection zone and/or control zone to be readily viewed without removalof the absorbent article from the wearer. In this embodiment, each layerof the absorbent article can have a transparent material, such thedetection zone and/or control zone of the lateral flow device can bevisualized even when the device is positioned on the bodyside liner. Forexample, referring to FIG. 7, each layer of the exemplary diaper 100 hasa transparent portion allowing viewing of the detection zone 20 andcontrol zone 22 through its entire construction. As shown, the bodysideliner 102, the absorbent core 103, and the outer cover 104 have atransparent window 105 that are aligned to allow viewing through thediaper 100. In other embodiments, the detection zone and/or control zonemay extend through a hole or aperture in the absorbent article forobservation. In still other embodiments, the detection zone and/orcontrol zone may be extended out of the absorbent article through thewaist or leg region when worn by the user.

Alternatively, the lateral flow device can be attached to the absorbentarticle such that the signal is not visible until removal of theabsorbent article from the wearer. For example, the device can beattached to the bodyside liner 102 such that the entire lateral flowdevice is concealed when the absorbent article is in use. Then, when theabsorbent article is removed, the user or caregiver can read the signaldisplayed on the device.

For instance, referring to FIG. 4, a lateral flow assay device 10 may beattached to the bodyside liner 102. The sample zone 16, positioned atone end of the assay device 10, is strategically positioned in thediaper 100 so that urine discharged by the wearer can travel to thesample zone 16 for collection of at least a portion of the dischargedurine therein. The absorbent material 18 is also provided at the otherend of the assay device 10 to hold part of the sample and to promotewicking or capillary flow in the device 10.

In one particular embodiment, the device 10 is positioned on thebodyside liner 102 such that the application zone 16 is located towardsthe crotch region for contact with discharged urine, and the absorbentmaterial 18 is positioned towards the waist region of the diaper 100. Assuch, the detection zone 20 and the control zone 22 are positioned awayfrom the crotch region of the diaper, helping to inhibit anycontamination from the urine discharged by the wearer.

FIG. 4 illustrates the assay device 10 as being placed directly onto thebodyside liner 102 of the absorbent article 100. Alternatively, theassay device 10 may be partially or completely encased within a thinfilm (not shown) except for the sample zone 16, which remains exposed tothe bodily fluid (e.g., urine) being tested. Such embodiments may bedesirable so as to inhibit other components of the assay device 10,other than the sample zone 16, from receiving the bodily fluid directlyfrom the wearer or from the layers of the absorbent article 100. Forexample, the assay device 10 may operate more effectively if the wickingzone is shielded so that it draws the bodily fluid only from sample zone16 and not from the absorbent article 100. Such thin film may beconstructed, for example, from a variety of materials including polymerssuch as polyethylene, polypropylene, polycarbonate, and others.

For each of the embodiments described above, the assay device 10 may beattached onto the absorbent article using a variety of techniques ormechanisms. For example, the assay device 10 may be attached using anyknown attachment mechanism, such as adhesive, ultrasonic, thermal bonds,etc. Suitable adhesives may include, for instance, hot melt adhesives,pressure-sensitive adhesives, and so forth. When utilized, the adhesivemay be applied as a uniform layer, a patterned layer, a sprayed pattern,or any of separate lines, swirls or dots. Alternatively, the assaydevice 10 may be connected using conventional fasteners, such asbuttons, hook and loop type fasteners, adhesive tape fasteners, and soforth. By way of further example, pockets or apertures may be built intoone or more layers of the absorbent article to fix the position of theassay device 10. In short, a variety of configurations may be used tosecure assay device 10 into a position that helps ensure contact withthe bodily fluid to be tested.

For example, referring to the embodiment shown in FIG. 2, the lateralflow device 10 has an adhesive layer 24 applied to the backside ofsupport 12. Adhesive layer 24 is shown protected with a peel strip 26covering the adhesive layer 24, which can be peeled away to expose theadhesive layer 24 when the user is preparing to adhere device 10 to theabsorbent article. The peel strip 26 can be any suitable layer, such asa film or fibrous web configured to release from the adhesive layer 24while protecting its adherence capabilities.

In another embodiment, such as the exemplary embodiment shown in FIG. 3,the device 10 is shown having hook-like elements 28 for use in attachingto the bodyside liner of an absorbent article. The hook-like elements 28can be those typically used in a hook and loop fastener, and maysufficiently attach to a bodyside liner formed from a nonwoven web,since the nonwoven web can have sufficient spaces between fibers for thehook-like elements 28 to attach. However, the absorbent article can beconfigured for attachment to the hook-like elements 28 by havingloop-like elements located on the absorbent article (such as on thebodyside liner). Alternatively, the absorbent article can be configuredwith a loop-like structure located on the bodyside liner 102 to engagethe hook-like elements 28 of the device 10.

In other embodiments, the absorbent article 100 can be configured toattach to a lateral flow device 10. For example, the absorbent articlecan be provided with an adhesive protected by a peel strip, such thatthe adhesive can be adhered to the later flow device when exposed.

In another embodiment, the later flow device can be provided within aninsert. The lateral flow device can be incorporated within the insert inany manner, as long as a reading of the detection zone and control zonecan be accomplished. For example, the lateral flow device can be placedjust below the cover, and the area of the liner where the detection zoneand the control zone are located can be transparent such that the signalcan be read or viewed.

For example, referring to the exemplary embodiment shown in FIG. 5, aninsert 110 is provided with absorbent material 114 positioned encasedwithin a cover formed from a back coversheet 112 and a top coversheet116. The lateral flow device 10 is shown positioned between the backcoversheet 112 and the absorbent material 114. The back coversheet 112is provided on its exposed side 110 with an adhesive layer configured toadhere the insert 110 to the bodyside liner of an absorbent article. Assuch, the insert 110 can be positioned between the bodyside liner of anabsorbent article and the skin of the wearer. Thus, upon insult of theabsorbent article by the wearer, the insert 110 is wetted with urine,and the application zone 16 of the lateral flow device 10 can contact asufficient amount of urine.

In one particular embodiment, the absorbent capacity of the absorbentinsert 110 can be less than that of the absorbent article to which it isattached. As such, the absorbent core of the absorbent article canattract a majority of insulting fluid. However, the absorbency of theabsorbent insert 110 is sufficient to provide enough of the insultingfluid to the lateral flow device 10 for a sufficient reading. In oneembodiment, for instance, the absorbent insert can be substantially freefrom superabsorbent material. Accordingly, the absorbent insert can beconfigured to absorb less than 20% of total bodily fluid absorbed by theabsorbent article and the absorbent insert, such as less than about 15%.In some embodiments, the absorbent insert is configured to absorb lessthan 10% of total bodily fluid absorbed by the absorbent article and theabsorbent insert, such as less than about 5%.

Although the insert is disclosed as including absorbent material 114, itis to be understood that the insert does not have to include anyabsorbent material. For example, in one embodiment, the insert cansimply be constructed of the lateral flow device encased within a cover.In either embodiment, the top coversheet 116 can be similarlyconstructed to that of any bodyside liner of an absorbent article, suchas those bodyside liners described above with reference to the absorbentarticles. Likewise, the back coversheet 112 can be similar to thoseouter covers described above with reference to the absorbent article.However, in some embodiments, the back coversheet 112 can be liquidpermeable, allowing the bodily fluid to defuse through the backcoversheet 112, and into the absorbent article to which it is attached.Thus, in some embodiments, the back coversheet 112 can be constructed ofany material described above with reference to the bodyside liners ofthe absorbent articles. In one particular embodiment, the backcoversheet 112 and the top coversheet 116 are constructed of the samematerial.

In one particular embodiment, the top coversheet 116 can be providedwith a transparent window 118 enabling the user or caregiver to view thedetection zone 20 and the control zone 22 through the bodyside liner116. Thus, upon removal of the absorbent article having the absorbentinsert attached thereto, the user can visually inspect the lateral flowdevice 10 to determine the presence or absence of the targeted analyte.Referring now to the exemplary embodiment shown in FIG. 6, the absorbent110 is adhered to absorbent article 100. The insert 110 is shown havinga transparent window 118 for viewing the detection zone 20 and thecontrol zone 22 of the lateral flow device 10 located within theconstruction of the insert 110. Various methods can be utilized toattach the insert 110 to the absorbent article 100. For example, theabsorbent insert 110 can be adhered to the bodyside liner 102 of theabsorbent article 100. Alternatively, the absorbent insert 110 can bemechanically fastened to the absorbent article, such as through the useof hook and loop fasteners and the like.

IV. Kits and Methods

In one embodiment, the lateral flow device can be provided in a kitincluding both the device and an absorbent article. As discussed above,the lateral flow device can be provided with or without an attachmentmechanism attached to it, or may be provided within the construction ofan absorbent insert. Likewise, the absorbent article may be providedwith an attachment mechanism configured to be attached to the lateralflow device or absorbent insert. Thus, the kit can include any number ofconfigurations of a lateral flow device and an absorbent insert, as longas the combination allows for attachment of the lateral flow device tothe absorbent article.

In yet another embodiment, a method for detecting the presence orabsence of an analyte in a bodily fluid, such as urine, is generallydisclosed. The method can include attaching a lateral flow device to abodyside liner of an absorbent article. Any of the lateral flow devicesdescribed above can be attached to any of the absorbent articlesdescribed above. As such, any of a variety of different combinations oflateral flow devices and absorbent articles can be used within themethod.

While the invention has been described in detail with respect to thespecific embodiments thereof, it will be appreciated that those skilledin the art, upon attaining an understanding of the foregoing, mayreadily conceive of alterations to, variations of, and equivalents tothese embodiments. Accordingly, the scope of the present inventionshould be assessed as that of the appended claims and any equivalentsthereto.

1. An absorbent article for testing a bodily fluid suspected ofcontaining an analyte, the absorbent article comprising: an outer cover;a bodyside liner; an absorbent core positioned between the outer coverand the bodyside liner; and a lateral flow device comprising achromatographic medium that defines a detection zone, the detection zonebeing configured for exhibiting a signal indicative of the presence orabsence of the analyte in the bodily fluid, wherein the lateral flowdevice is attached to the bodyside liner of the absorbent article.
 2. Anabsorbent article as in claim 1, wherein the lateral flow device isreleasably attached to the bodyside liner of the absorbent article. 3.An absorbent article as in claim 1, wherein the chromatographic mediumincludes a control zone for indicating that a sufficient volume of thebodily fluid has been received by the lateral flow device.
 4. Anabsorbent article as in claim 3, wherein the lateral flow device furthercomprises a control reagent that is capable of being detected within thecontrol zone.
 5. An absorbent article as in claim 1, wherein the lateralflow device further comprises a sample application zone.
 6. An absorbentarticle as in claim 1, wherein the lateral flow device further comprisesa capture reagent that is substantially non-diffusively immobilizedwithin the detection zone.
 7. An absorbent article as in claim 6,wherein the capture reagent is a specific binding member.
 8. Anabsorbent article as in claim 6, wherein the capture reagent is adiazonium ion or a derivative thereof.
 9. An absorbent article as inclaim 6, wherein the lateral flow device further comprises a diffusivelyimmobilized reagent.
 10. An absorbent article as in claim 9, wherein thediffusively immobilized reagent includes a specific binding member. 11.An absorbent article as in claim 9, wherein the diffusively immobilizedreagent includes an aromatic ester substrate.
 12. An absorbent articleas in claim 1, wherein the lateral flow device includes an absorbentmaterial that receives the bodily fluid after flowing through thechromatographic medium.
 13. An absorbent article as in claim 1, whereinthe lateral flow device is adhesively attached to the bodyside liner ofthe absorbent article.
 14. An absorbent article as in claim 1, whereinthe lateral flow device is attached to the absorbent article using ahook and loop type fastener.
 15. An absorbent article as in claim 1,wherein the lateral flow device comprises hook-like members forattaching to the bodyside liner of the absorbent article.
 16. Anabsorbent article as in claim 1, wherein the lateral flow device islocated within the construction of an insert, wherein the insertcomprises a cover encasing the lateral flow device, and wherein theabsorbent insert is attached to the absorbent article.
 17. An absorbentarticle as in claim 16, wherein the insert comprises an adhesive layeron an exposed surface for attaching to the bodyside liner.
 18. Anabsorbent article as in claim 16, wherein the insert further comprisesabsorbent material configured to absorb less than 20% of the bodilyfluid discharged into the absorbent article.
 19. An absorbent article asin claim 18, wherein the insert is substantially superabsorbent free.20. An absorbent article as in claim 16, wherein the insert comprises atransparent window allowing the detection zone to be viewed by a user.21. An absorbent article as in claim 1, wherein detection zone of thelateral flow device is capable of being viewed when the absorbentarticle is worn by a wearer.
 22. An absorbent article as in claim 21,wherein each of the outer cover, the absorbent core, and the bodysideliner comprises a transparent window, and wherein the outer cover, theabsorbent core, the bodyside liner, and the lateral flow device arearranged such that the detection zone of the lateral flow device isviewable through the transparent window when the absorbent article isworn by a wearer.
 23. An insert for testing a bodily fluid suspected ofcontaining an analyte, the insert comprising: a cover; a lateral flowdevice encased within the cover, the lateral flow device comprising achromatographic medium that defines a detection zone, the detection zonebeing configured for exhibiting a signal indicative of the presence orabsence of the analyte in the bodily fluid; and an attachment mechanismconfigured to attach the insert to a bodyside liner of an absorbentarticle.
 24. An insert as in claim 23, wherein the lateral flow deviceincludes an absorbent material that receives the bodily fluid afterflowing through the chromatographic medium.
 25. An insert as in claim 23further comprising an absorbent material encased within the cover. 26.An insert as in claim 25, wherein the absorbent material is configuredto absorb less than 20% of the bodily fluid discharged into theabsorbent article.
 27. An insert as in claim 25, wherein the insert issubstantially superabsorbent free.
 28. An insert as in claim 23, whereinthe insert is releasably attached to the bodyside liner of the absorbentarticle.
 29. An insert as in claim 23, wherein the chromatographicmedium includes a control zone for indicating that a sufficient volumeof the bodily fluid has been received by the lateral flow device.
 30. Aninsert as in claim 23, wherein the lateral flow device further comprisesa sample application zone.
 31. An insert as in claim 23, wherein thelateral flow device further comprises a capture reagent that issubstantially non-diffusively immobilized within the detection zone. 32.An insert as in claim 23, wherein the attachment mechanism comprises anadhesive layer on an exposed surface of the cover.
 33. An insert as inclaim 23, wherein the insert comprises a transparent window allowing thedetection zone to be viewed by a user.
 34. An insert as in claim 23,wherein the attachment means comprises a plurality of hook-like memberson an exposed surface of the cover for attaching the insert to thebodyside liner of the absorbent article.
 35. A method for detecting thepresence or absence of an analyte in urine, the method comprising:attaching a lateral flow device to a bodyside liner of an absorbentarticle, wherein the lateral flow device comprises a chromatographicmedium that defines a detection zone, the detection zone beingconfigured for exhibiting a signal indicative of the presence or absenceof the analyte in the bodily fluid, wherein the lateral flow device orthe absorbent article comprises an attachment mechanism.
 36. A method asin claim 35, wherein the lateral flow device is located within theconstruction of an insert comprising a cover, and wherein the attachmentmechanism is configured to attach the absorbent insert to the absorbentarticle.